At least 18 civilians, including a 12-year-old girl and a humanitarian worker, have been killed in Yarmouk since the armed group which calls itself the Islamic State (IS) attacked and mostly seized the Palestinian refugee camp over the past week, said Amnesty International.

Thousands more are at risk as Syrian government forces have intensified the shelling and aerial bombardment of the camp in response to the IS takeover of the area, including by dropping barrel bombs. Civilians have also come under sniper fire and been caught up in clashes between armed groups, notably IS and the mostly Palestinian Aknaf Beit al-Maqdis.

“For civilians still trapped in Yarmouk life is an agonizing struggle for survival. After enduring a crippling two-year-long government-imposed siege, now they are pinned down by sniper fire fearing for their lives as shelling and aerial attacks escalate,” said Hassiba Hadj Sahraoui, Amnesty International's Deputy Middle East and North Africa Director.

For civilians still trapped in Yarmouk life is an agonizing struggle for survival.

Despite the escalation in fighting, both Syrian government forces and IS fighters have refused to allow any medical or humanitarian aid into the camp, leaving dozens of injured people without access to crucial medical and other life-saving assistance. One of Yarmouk’s two surviving medical facilities, the Palestine Hospital, was struck by a missile injuring six volunteers on 1 April.

“The main injuries here are caused by sniping and shelling…,” a medical worker in Yarmouk told Amnesty International.

“The main illnesses are heart and chest conditions, diarrhoea and infections – and all are worsened by malnutrition. We have a severe lack of medicines and medical equipment and we have an urgent need for rehydration liquids, blood bags and antibiotics.”

There are no relief organizations left working in the camp.

“Immediate and unfettered access to Yarmouk by independent humanitarian agencies is desperately needed to alleviate this relentless suffering,” said Hassiba Hadj Sahraoui.

According to local activists, Zeinab Daghestani a 12-year-old girl, was shot dead by a sniper on 7 April while trying to flee to the calmer southern part of Yarmouk. Other civilians killed include Majed al-Omari, a humanitarian worker for Jafra Foundation, a relief organization, who is believed to have been shot dead in cross-fire on 3 April. Jamal Khalefe, a 27-year-old media activist, was killed during heavy shelling on the same day. Another young

Palestinian refugee, Hussein Taha, was killed on 6 April when his home was struck by a barrel bomb.

Residents told Amnesty International that some 25 barrel bombs were dropped on Yarmouk over the past week, mostly at night.

Civilians in Yarmouk have found themselves caught between the prospect of IS abuses and the imminent danger posed by government bombardments.

The neighbourhoods of Palestine Street, Mansoureh Street and the Martyrs’ Cemetery, still predominantly civilian areas although some IS fighters had taken up positions there, were targeted in government attacks.

“The use of barrel bombs against a besieged and starving civilian population is yet another demonstration of the Syrian government flouting international humanitarian law and its callousness towards civilians. Sparing civilian life does not appear to come into the equation when they decide to bomb an area,” said Hassiba Hadj Sahraoui.

“Shelling and dropping barrel bombs on a populated civilian area is a war crime. All such attacks must end immediately. All sides should also take all feasible precautions to minimise harm to civilians.”

The use of barrel bombs against a besieged and starving civilian population is yet another demonstration of the Syrian government flouting international humanitarian law and its callousness towards civilians.

“For the civilians the situation is increasingly worse,” one resident said. “No water, no food, no medicine.”

Some 18,000 civilians remain besieged in Yarmouk. Nearly two years of a brutal government siege imposed in July 2013, has led to a devastating humanitarian crisis. By March 2014, at least 194 people in the camp had died, mostly as a result of starvation and a lack of medical care.

One civilian activist in Yarmouk told Amnesty International that two more residents died of starvation this week.

“The scale of humanitarian suffering and desperation in Yarmouk is overwhelming. All warring parties must grant immediate access to humanitarian agencies so that they can urgently meet the needs of the civilian population and assist in the evacuation of those who wish to flee to safer areas,” said Hassiba Hadj Sahraoui.

IS fighters’ entry to Yarmouk on 1 April 2015 was reportedly facilitated by Jabhat al-Nusra, an armed group whose fighters were already present in the camp. They are fighting armed groups including Aknaf Beit al-Maqdis, said to be close to the Palestinian Hamas organization, and Jaish al-Islam. Residents say that three captured Palestinian fighters were beheaded by IS. Prior to 2011 Yarmouk hosted the country’s largest Palestinian refugee population as well as many thousands of Syrian nationals.